Thomas, S. ORSTOM, thomas@bouake.orstom.ci
Cecchi, P. M. ORSTOM, cecchi@bouake.orstom.ci
Corbin, D. ORSTOM, corbin@bouake.orstom.ci
Lemoalle, J. ORSTOM-GAMET, jacques.lemoalle@mpl.orstom.fr

 
THE MINOR IMPORTANCE OF PERIPHYTIC COMMUNITIES ON TOTAL PRIMARY PRODUCTION IN A SMALL AFRICAN TROPICAL RESERVOIR : AN ECOSYSTEM STUDY (BROBO, IVORY COAST).
 
From June 1997 to September 1998 the phytoplanctonic, periphytic (epiphytic/epipelic) and macrophytic communities from a small tropical reservoir at Brobo, Ivory Coast, were studied. The aim of the study was to assess their relative contribution to the total primary production of the ecosystem during a complete dry hydrological cycle (lack of flood during 1997). Since the lake was not cleared before filling, there was a large number of flooded trees that could offer an important surface potentially available to periphyton development. An adapted sampling methodology was developed for each type of primary compartment with respect to their specific spatial and temporal scales of variability. Special attention was devoted to tree periphyton biomass whose variations have been also studied using artificial substrata (thin transparent plastic stripes). Flooded surface of trees were estimated using aerial photographs. After extrapolating the periphytic biomass of artificial substrata to the whole reservoir, results show that the contribution of this community to the total ecosystem primary production is very low (about 1%). Main contributors to the total primary production during the hydrologic cycle were phytoplancton and microphytobenthos. Inter-competition for underwater irradiance is also described and analysed and is related to phytoplancton development.
 
Day: Monday, Feb. 1
Time: 02:15 - 02:30pm
Location: Sweeney Center
 
Code: SS45MO0215S